1. Field of the Invention
The present invention relates to a method for shielding discarded or unwanted items provided with a Radio Frequency Identification (RFID) tag.
2. Description of the Prior Art
Various technologies have been developed for identifying and tracking objects. The most common involves application of identifying bar codes to objects and optically scanning those codes to identify the objects or certain other relevant coded characteristics, e.g., size, model, price, etc. A more recent development is radio frequency identification technology, commonly known as RFID technology. RFID devices, commonly called RFID tags, are thin transponders (transceivers) that include an integrated circuit chip having RF (radio frequency) circuits, control logic and memory, plus an antenna, all mounted on a supporting substrate. RFID devices are either of the active type or passive type. The active type RFID tags include a battery for powering a transceiver. The passive type RFID tags have no battery and derive its energy from the RF signal used to interrogate it. The RFID transponder operates to receive, store and transmit object-identifying data to and from the memory within the chip. The device functions in response to coded RF signals received from a base station. Typically it reflects the incident RF carrier back to the base station, and information stored in the device is transmitted back to the interrogating base station by modulating the reflected signal according to the programmed information protocol.
Recent developments have produced thin RFID tags on flexible organic substrates, with the overall thickness of the tags being of the order of a fraction of a millimeter. Various materials have been used as the organic substrate of commercial RFID tags, including but not limited to thin flexible films of polyester such as Mylar®™ or a polyimide such as Kapton®™. The antenna may comprise preformed wires that are attached to the substrate, but more commonly it is a thin film element, usually consisting of copper lines formed by plating copper onto the flexible organic substrate or by etching in the case where the substrate is a copper/organic material laminate. Further information regarding the manufacture and use of RFID transponders is provided by U.S. Pat. No. 5,497,140, issued Mar. 5, 1996 to J. R. Tuttle; U.S. Pat. No. 5,528,222, issued Jun. 18, 1996 to P. A. Moskowitz et al.; U.S. Pat. No. 5,566,441, issued Oct. 22, 1996 to M. J. C. Marsh et al.; U.S. Pat. No. 5,661,473, issued Aug. 26, 1997 to J. P. Paschal; U.S. Pat. No. 5,682,143, issued Oct. 28, 1997 to M. J. Brady et al.; U.S. Pat. No. 5,955,951, issued Sep. 21, 1999, and U.S. Pat. No. 6,018,299, issued Jan. 25, 2000 to N. H. Eberhardt. The greatest disadvantage of bar codes is that they are not dynamic carriers of information, require direct or proximal line of sight contact for reading and are adversely impacted by dirt, grime and soiling. With bar codes the stored information is static. Consequently information stored in bar codes on an object cannot be updated as it travels, for example, from a shipper to a receiver. In contrast, RFID tags are programmable and offer the capability of updating recorded information at any time and in real time. RFID transponders are of particular value to industries that need to quickly and accurately track and manage very large numbers of objects. The passive type of RFID tag is particularly valuable in relation to inventory management and control because it offers a long life data storage and retrieval capability, since it draws its energy and transfers information in the form of low power radio waves resulting from operation of the read/write module of a base station.
Small lightweight RFID foil tags have long been implemented in security systems in retail stores. The foil RFID tag is secured to a product and is capable of storing information regarding the product or sale status. A RFID interrogator is used to read the tag, record the sale of the item, and write to the tag to change the status to purchased, to allow the product and tag to leave the store without tripping the stores security alert system. The technology to use such RFID tags for inventory and assembly lines etc. are known in the art to facilitate reading and writing to small RFID foil tags without contact and without the need for a power supply to the tag itself. Rather, the tag relies on modulated radio frequencies from the RFID reader/writer to exchange information. Various RFID systems are disclosed in U.S. Pat. Nos. 6,717,507; 6,806,808; 5,055,659; 5,030,807; 6,107,910; 6,580,358; and 6,778,847 each of which are hereby incorporated herein by reference.
The energy returned to the RFID reader (interrogator) is at low power levels to prevent scatter and to control the signal path. These signals are returned to the reader over a narrow field and their reception may be compromised by interference from devices capable of emitting radio-frequency signals such as cordless phones, computers, manufacturing equipment etc.
In retail, manufacturing or wholesale industries, among possible causes of signal contamination would be carelessly discarded RFID tags or discarded and/or unwanted items (objects), such as retail products or goods, tagged with this technology. For example in a supermarket warehouse setting, an empty RFID carton may be left on a shelf after the contents have been removed to stock the retail portion of the store. If the tag has not been inactivated, when the inventory is checked, the signal could be diluted or incorrectly signal that the carton is in stock, albeit empty, and therefore the inventory will read at a higher quantity. Another supermarket or retail store scenario could take place at checkout where a customer decides that a certain item (RFID tagged) is not wanted and the cashier puts it aside till it can be later collected and returned to inventory. If this item is in the vicinity of the reader it could compromise the signal or be read and falsely added to the customer's bill or that of the next customer in line. Other examples include tracking RFID material from freight cars which, if thrown away like a candy wrapper, would continue to emit a signal (if not deactivated) which could interfere with the reader.
With this in mind, a need exists to develop a method for shielding or disposing products or goods that include an RFID tag in a non-destructive manner in retail and other industries so as to isolate the RFID tag from the RFID tag reader.